Submersible mining, lifting and towing barge



Nov. 30, 1965 G. w'. LEHMANN 3,220,372

SUBMERSIBLE MINING, LIFTING AND TOWING BARGE Filed Sept. 6, 1961 2Sheets-Sheet 1 FIG. I AV /8 :1,1m C B 12,/2a

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24a 23a I3 25,25a 23 24 INVENTOR GUENTHER W. LEHMANN Nov. 30, 1965 G. w.LEHMANN 3,220,372

`SUBNERSIBLE MINING, LIFTING AND TowING BARGE F'iied sept. 6, 1961 2Sheets-sheet z \N k g f I4 I5 36 32 INVENTOR GUENTHER W. LEHMANN UnitedStates Patent C) 3,220,372 SUBMERSIBLE MINING, LIFTING AND TWING BARGEGuenther W. Lehmann, 1445 Oak St., @aklaud 12, Calif. Filed Sept. 6,1961, Ser. No. 136,271 9 Claims. (Cl. 114-16) The present inventionrelates to a barge specially designed for mining operations at the seabottom.

Mining operations at the sea bottom are usually performed by dredgingwork up to moderate water depths. At greater water depths, as forinstance in gold mining operations oft` the Mexican coast, smallquantities of sand are suctioned by way of a hose into a small submergedcontainer for later processing at the surface.

In order to avoid repeated lifting of a great number of small quantitiesof minerals or other desirable materials from the sea bottom where thewater depth makes direct dredging prohibitive, it is proposed inaccordance with this invention to use a submersible barge which iscapable of lifting great quantities of material from the sea bottom tothe surface, and then to tow the barge from the site of mining operationto the site of processing.

Loading of the barge while resting on the sea bottom Will be performedby special equipment like suction hoses or similar apparatus which aredirectly or remotely controlled underwater devices as developedelsewhere.

Upon completion of loading, the barge is raised to the surface Iand thentowed to a plant ashore or to a floating plant for processing of theminerals or other material from the sea bottom. Employing a submersiblebarge as described hereinafter makes possible hauls of large quantitiesof minerals in a single operation, thus avoiding otherwise repeatedhauls of small quantities which operation requires a greater time perton material hauled, particularly at the presence of great water depths.By using a mining barge of the present invention, underwater miningoperations can be brought to a higher economical level.

In case of emergency a barge according to this invention may also beused for ready available underwater storage of ammunition and militaryequipment in watertight containers and for emergency foodstuff.

A barge intended to be lowered to the sea bottom and to be raised fromthe sea bottom to the surface in loaded condition has to be designed insuch a way that said operation can be conducted safely and efliciently.Positive stability and level trim have to be assured in all phases ofoperation, i.e. during submersion, While raising the barge from the seabottom and when the barge is at the surface. In particular during thecritical phase of leaving the surface while submerging, surfacestability should still be present when gravity stability developsgradually by raising the center of buoyancy and vice versa. Specialdevices have to be employed for keeping the barge on even trim duringsubmerging and raising in loaded or empty condition. While the barge isresting on the sea bottom, special devices have to be provided whichrelease the barge from the Water pressure which otherwise wouldpin-point the barge on the sea bottom. It is generally known that suchforces, usually referred to as adhesion forces, are of great magnitudeand increase with the water depth sometimes to such an extent thatseparating a structure from the sea bottom is a diiiicult operation.

In order to solve the aforementioned technical problems an underwatermining, lifting and towing barge is designed and constructed accordingto the present invention in the following manner.

The barge consists of one or more open cargo cells and is equipped withwing tanks for ballasting and producing buoyancy. The buoyancy or wingtanks are so arranged and shaped that the buoyancy center is all thetime above the weight center of the entire system While the barge is insubmerged condition. For providing suicient overcrossing of surface andweight stability and further to raise the center of buoyancy versus thecargo space center, special tanks are provided on deck at the fore andaft end of the barge. When the deck is just below the waterline duringraising and the buoyancy center is about to pass the weight center,there is already a certain waterplane inertia present by virtue of theaforementioned end tanks on deck. In this Way, a small surface stabilityis present when the gravity stability diminishes. When the barge isemerging further, a great waterplane inertia develops as soon as thedeck touches the surface. The present problem is similar to that offloating docks with regard to the critical stability phase at Waterlevels between the ships bottom and the pontoon deck of a iioating dock.

The fore and aft tanks provided above the deck of the present bargefulfill a second purpose as trim stabilizer. The deck tanks are halffilled with water and are connected to each other by an air and waterpipe. Fore and aft tanks form a closed circuit. In instances where cargoproduces a trim moment, a pumping device, preferably a screwpump, ispumping water ballast from one deck tank to the other and thuseliminates the trim moment. The air above the water within the partiallylled water tanks and the ballast water are exchanged from one end to theother end of the barge as per trim requirements.

Ballasting of the barge for submersion and raising of the barge is doneby conventional sea valves and air pressure. However, a specialarrangement of overliow pipes and flaps has to be provided in order tomake the underwater mining barge workable. To accomplish this, one ormore customary sea valves are installed in the midship wing tanks. Whenthe sea valves are opened in order to start submersion of the barge,midship wing tanks on port and starboard are iirst filled with ballastWater. Air escapes through air pipes which are carried from top tobottom of the adjacent and each following wing tank in the directiontoward the end compartments. The end compartments, which form the foreand aft peak tanks respectively, are connected to each other by aspecial air pipe for supplying air to both end compartments from one endof the barge and furthermore to provide an air escape simultaneously,from both end compartments and consequently from all other wing tanksof the forward and aft group.

' The height of the overiiow from the first midship ballast wing tank tothe adjacent tank is determinedby the freeboard which has been reachedwhen the midship wing tanks are gradually filling with Water ballast.Since the then reached inside water level of the midship wing tanksprovides trapped air in consideration of the height of the overliowpipe, the capacity of the midship wing :tanks and adjacent wing tanksand the height of the overflow of each tank has to be designed in such amanner that with a fully submerged barge, the trapped air produces a notdestroyable buoyancy of the desired quantity at a certain depth whichwill partly compensate the weight of the barge while resting on the seabottom. Such relief of weight is sometimes desirable when miningoperations have to have conducted at sea bottoms of insuiiicientsupporting capacity.

Since the end compartments are connected by an air pipe, only one airsupply hose is required. During raising, air pressure is blowing waterballast from the end compartments rst and then successively fromadjacent and following compartments in the direction of the midship wingtanks from Where the water ballast of all group compartments is pressedto the outside through the open sea valves. It should be appreciatedthat during the entire operation from submerging through loading andraising of the barge, the sea valves are permanently open. When thebarge has reached the sea level they will be closed for the towing trip.Surplus compressed air, if any, is then released from all tanks.

The open cargo space is made iioodable by openings at the longitudinalwing tank bulkheads. The openings are closed by spring-loaded flaps witha slight pressure of the flap against the coa-ming of the opening on thecargo space side. When water ballast enters the wing tanks, the waterpressure opens the ap slightly against the spring force of the flap andwater enters the cargo space from the wing tanks. When the barge isfilled with minerals or other material from the sea bottom, the flap isirmly pressed by the weight of the cargo and is then tightly closedagainst air pressure from the wing tanks when raising of the barge isstarted.

Instead of using air pressure through a hose from a special tender, itis the preferred procedure to employ chemicals which produce pressuregas when they come in contact with sea water as described in my patentapplication Serial Number 816,806, now Patent No. 3,080,844.

The barge should not rest directly on the sea bottom but rather on aspecially built grid. The grid consists of a heavy bottom plate andpreferably T-shaped girders on which the barge is resting in the mannerof a ship docked in a iioating dock. In this way, the bottom of thebarge is exposed to water pressure from underneath and only a smallpercentage of the barge bottom area is covered by lianges of theT-girders. This will greatly reduce the adhesion force which otherwisewould pinpoint the barge on the sea bottom.

The bottom of the grid is a full plate, preferably Without holes inorder to produce a great adhesion force. A firm adhesion of the grid onthe bottom of the sea is desirable for two reasons. First, the gridserves so to say as a docking place for the barge; second, guidanceropes .attached to buoys on the surface and to the grid intended asguidance means for the barge during submersion may exert great forces onthe guidance ropes by -currents and swaying of the barge. A full plateof the grid ensures the maximum of adhesion force for proper anchoringof the system under prevailing circumstances. The grid may be lowered tothe bottom of the sea at the first submersion of the mining bargewhereby the barge itself serves as a vehicle for lowering the grid and`the entire system. The grid remains on the sea bottom during the`mining expedition and may later be pulled to the surface separately ormay be considered as lost investment after mining at this particularsite is abandoned.

The above and other features of the invention become more apparent andwill be more fully described in the following detailed description of apreferred embodiment, taken in conjunction with the accompanying drawingwherein.

FIG. 1 is an inboard profile of one embodiment of the barge according tothe invention;

FIG. 2 isa plan view of FIG. 1 in deck level;

FIG. 3 is a cross section of FIG. 1 at A-A;

FIG. 4 is a cross section `of FIG. l at B-B;

FIG. 5 is a cross section of FIG. l at C-C;

FIG. 6 is a modification of the pressure gas supply installation;

FIG. 7 shows the barge on the sea bottom with ooded tanks;

FIG. 8 shows the barge on the sea bottom at the beginning of dischargeof ballast water by air pressure;

FIG. 9 shows the barge while leaving the sea bottom and raising to thesurface at a slight trim;

FIG. 10 shows the barge just below the surface with deck-tanks partlyemerging;

FIG. l1 shows the barge in fully Vraised condition at the surface readyfor towing.

A barge 1 with open cargo spaces 2, 3 has on port and starboard sidewing tanks 4, 5, 6, 7 and 4a, 5a, 6a, 7a and end compartments 8, 9.Above the deck 10 of the barge 1 and above end compartments 8, 9 thereare independent buoyancy, stability and trim tanks 11, 12 and 11a, 12a.A transverse bulkhead 13 subdivides the cargo space, wing tanks and endcompartments in two groups fore and aft. Midship wing tanks 4, 5, 4a, 5aare equipped with bottom sea valves 14, 15. Overiiow pipes 16, 17 and16a, 17a are arranged in such way that the lower opening of the pipe isin a recess at the bottom of each tank and the upper opening of thepipes below the tank top with opening in direction to the adjacent tankand in a direction from the barge ends to the midship wing tanks.Employing this arrangement of overflow pipes, water ballast is blownsimultaneously from both ends and successively from tank to tank towardthe midship wing tanks 4, 5 and 4a, 5a where the ballast Water of allcompartments escape through the open sea valves 14, 15, as best shown inFIGS. 8 and 9. Air pressure .is supplied via a hose 18 at only on end ofthe barge with direct access to one end compartment and connected by apipe 19 to the other end compartment.

Deck tanks 11, 12, 11a, 12a are connected by water pipes 20, 20a and airpipes 21, 21a kand are permanently filled at about half the height ofthe tank with water 22 and air 22a. Screw pumps 2,3, 23a activated by alevelling contact (not shown) are pumping ballast water in eitherdirection from one deck tank to the other deck tank as per trimrequirements. Screw pumps 23, 23a are housed in a watertight structure24, 24a.

Openings 26, 26a are provided at the lower portion of the longitudinalbulkheads 27, 27a and are closed by flaps 28, 28a which are slightlypressed by a springloaded hinge from the cargo spaceside against thecoaming of the opening 26, 26a. When the barge is loaded with minerals29, FIG. 5, the weight of the cargo load, in addition to the spring loadof the hinge, is pressing the aps 28, 28a against the openings 26, 26a.In this way, openings 26, 26a are tight against water and air pressurewhen the ballast water is blown out from the wing tanks.

The barge is resting on a grid 30 on the bottom of the sea 31. The lowerpart of the grid 30 consists of a heavy plate 32 whereas the bottom ofthe barge 1 is resting on T-shaped girders 33 welded to the bottom plate32 as best illustrated in FIGS. 5 and 7. The grid is lowered to thebottom of the sea 31 together with the barge 1 at the beginning of themining operation. Once the grid 30 is properly placed on the ground,cables 34 which hold the grid 31) during lowering are released. Instead,guidance ropes 35 are `attached to the grid 30 and to buoys 35a at lthesurface. The barge 1 while submerging is guided by the ropes 35 to theproper place on the grid 30.

Fixed ballast 36 is attached to the bottom of the barge 1 for equalizingtop weights and to produce a slight aft trim for improved sea steadinessof the barge while under tow.

Wing tanks are designed with a great bilge radius or 5. in the shape ofa trapezoid 37 in order to raise the center of buoyancy as high aspossible. On the other hand, the cargo spa-ce has to be iilled withcargo to only 70 to 80 percent of the possible full capacity in order tokeep the center of weight below the buoyancy center when the system isin submerged condition.

The barge` 1 is resting on the grid 30 mainly with the fixed ballastprojection 36. Overhanging wing tanks support of the wings.

Upon loading, the barge 1 is resting on the grid 30 are equipped withlongitudinal girders 38 for proper at the bottom of the sea 31 with alltank compartments flooded as shown in FIG. 7. Trapped air 39 standingunder a pressure corresponding to the water depth relieves partly theweight of the barge and cargo on the grid 30.

When the barge 1 is going to be raised, air pressure blows the endcompartments 8, 9 first, pressing the water ballast of the endcompartmets through the pipes 17, 17a into the adjacent Wing tangs 6, 6aand 7, 7a, further through the pipes 16, 16a into the midship win-gtanks 4, 4a and 5, 5a ,from where the ballast water escapes to theoutside through the open valves 14, 15 on port and starboard side. Endcompartments and wing tanks are in this way successively emptied asshown in FIGS. 8, 9, 10 and 11.

After a certain amount of buoyancy has developed, the barge starts toraise from the grid 30 as illustrated in FIG. 9. It is Well possiblethat the barge starts raising with one end iirst due to a trim momentproduced by unsymmetrical cargo distribution in longitudinal direction.In such cases, screwpumps 23, 23a are shifting ballast water from onedeck tank to the other. Upon stabilizing of the trim moment the bargecontinues to raise at fairly even trim or rather may ascent with a smalloscillatory trim motion limited and controlled by the trim ballastingdevice 11, 12 and 23.

As soon as the barge 1 starts to raise from the grid 30, air supply viathe hose 18 is cut. It should be appreciated that only a small surplusof buoyancy against the underwater weight of the. system is required forinitiating a raising of the barge. From this instant additional airsupply is not only not required but even not desirable in so far as thecompressed air within the tank system expands while the barge isascending to water levels of smaller water pressure. In this way, moreand more buoyancy develops without additional supply of air and more andmore ballast water is blown out of the tanks by the expanding air. It isobvious that, when additional air should be delivered after raising ofthe barge at the initial phase, buoyancy will then develop even fasterresulting in an undesirable vehement raising motion.

After the barge has reached the surface with empty wing tanks and emptyend compartments as shown in FIG. 11, sea valves 14, are closed and airpipes 18 and 19 opened for release of any surplus air. Trapped water 40at the side of the cargo 29 is self-draining through pipes 41 as shownin FIG. 5.

The barge 1 will be submerged by merely opening the bottom sea valves14, 15 resulting in successive ballasting of the wing tanks, cargo spaceand end compartments while the air escapes through the pipe system 16,17, 18. Particular attention has to be paid to the height 42 of theoverflow pipes with regard to freeboard, ballast weight, weight of thebarge and buoyancy by trapped air 43 in the midship compartment 4, 4aand 5, 5a. If, for instance, the overow height of the wing tanks 4, 4aand 5, 5a at the overflow pipes 16, 16a is too high and above themeanwhile reached freeboard or draft, respectively, the barge remainsoating and does not submerge because additional water ballast can notenter the adjacent wing tanks Ifor further lowering of the barge.

Instead of using compressed air it is suggested to employ chemicalswhich are generating pressure gas upon contact with seawater, Chemicalsmay be housed in a special compartment 44 as shown in FIG. 6. Pellets ofchemicals may be activated by remote controlled electronic devices fromthe surface as described elsewhere.

While the invention has been described and illustrated in connectionwith certain preferred embodiments, it will be understood that manyvariations and modifications may occur to the skilled in the art,particularly after benefiting from the present teaching, withoutdeparting from the spirit and scope of this invention as defined in theappended claims.

What I claim is:

1. A system for controlling the trim stability, raising and lowering ofa submersible barge having a deck and a cargo space below the deck,which comprises (a) at least one pair of portside tanks and at least onepair of starboard tanks, the tanks of each pair extending from atransverse line through the center of gravity of said barge toward theforward and aft peaks of the barge, respectively,

(b) a forward tank and an aft tank at the forward and aft peaks,respectively,

(c) a pair of buoyancy tanks atop the forward tank and a pair ofbuoyancy tanks atop the aft tank, said buoyancy tanks being arrangedabove the deck plane, one tank of each pair being arranged portside andthe other tank starboard,

(d) an air supply,

(e) conduit means connecting the air supply to each of the forward andaft peak tanks,

(f) s ea valve means establishing communication between the water andthe portside and starboard tanks nearest said transverse line,

(g) overflow pipe means extending between adjacent ones of saidportside. and starboard tanks and said forward and aft tanks,respectively, whereby air pressure supplied through said conduit meansto said forward and aft peak tanks will simultaneously force waterballast in said tanks to ow from the forward and aft peak tanks towardthe midship tanks whence it escapes through the sea valve means, Whilewater admitted through said sea valve means will simultaneously forceair in said tanks to flow from the midship tanks toward the forward andaft tanks, respectively,

(h) ballast water partially filling said buoyancy tanks,

the remainder thereof being lled with air,

(i) pipes interconnecting the ballast water in the portside buoyancytanks and in the starboard buoyancy tanks, respectively,

(j) pipes interconnecting the air in the portside buoyancy tanks and inthe starboard buoyancy tanks, respectively, and

(k) pumping means delivering ballast water through the interconnectingpipes between the portside buoyancy tanks and the starboard buoyancytanks according to the trim requirements.

2. The system of claim 1, wherein two pairs of portside tanks and twopairs of starboard tanks are provided, two midship tanks and two tanksintermediate the midship tanks and the forward and aft tanks,respectively, being provided portside and starboard.

3. The system of claim 1, wherein said air supply consists of a supplyof chemical substances capable of evolving air in contact with water.

4. The system of claim 1, wherein each of said overow pipe means extendsIfrom a point near the top of one of said tanks nearer the transverseline to a point near the bottom of the adjacent one of said tanks.

5. The system of claim 1, wherein the ballast water lls the buoyancytanks to about half their height.

6. The system of claim 1, wherein said air-pressure controlled pumpingmeans consists of screw pumps in the pipes interconnecting the ballastwater, and

(l) a water-tight housing is provided for each screw pump.

7. The system of claim 1, further comprising 7 8 (n) tWo longitudinallyextending bulkheads defining References Cited by the Examiner the cargospace and separating the saine from said UNI A P portside and starboardtanks, said bulkheads defining TED ST TES ATENTS openings near thebottoni thereof, and 1 l ggussln r* g r 4 4 (0) Sprmgloaded aps forClOSmg Sald opemngs. 5 218871977 571959 Pity 114 16 3 8. The system ofclaim 1, further comprising (p) a xed ballast attached to the bottom ofthe barge and producing an aft trim. FERGUS S. MIDDLETON, PrimaryExmmner. 9. The system of claim 1, wherein said portside and RICHARD A.DOUGLAS, MILTON BUCHLER,

starboard tanks are of trapezoidal cross section. Examiners.

UNITED STATES APATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,220,372 November 30, 1965 Guenther W. Lehmann It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 5, line 9, strike out "support of the wings." and insert insteadare equipped with longitudinal girders 38 for proper support of thewings. line ll, strike out "are equipped with longitudinal girders 38for proper".

Signed and sealed this 27th day of December 1966.

Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A SYSTEM FOR CONTROLLING THE TRIM STABILITY, RAISING AND LOWERING OFA SUBMERSIBLE BARGE HAVING A DECK AND A CARGO SPACE BELOW THE DECK,WHICH COMPRISES (A) AT LEAST ONE PAIR OF PORTSIDE TANKS AND AT LEAST ONEPAIR OF STARBOARD TANKS, THE TANKS OF EACH PAIR EXTENDING FROM ATRANSVERSE LINE THROUGH THE CENTER OF GRAVITY OF SAID BARGE TOWARD THEFORWARD AND AFT PEAKS OF THE BARGE, RESPECTIVELY (B) A FORWARD TANK ANDAN AFT TANK AT THE FORWARD AND AFT PEAKS, RESPECTIVELY (C) A PAIR OFBUOYANCY TANKS ATOP THE FORWARD TANK AND A PAIR OF BUOYANCY TANKS ATOPTHE AFT TANK, SAID BUOYANCY TANKS BEING ARRANGED ABOVE THE DECK PLANE,ONE TANK OF EACH PAIR BEING ARRANGED PORTSIDEK AND THE OTHER TANKSTARBOARD, (D) AN AIR SUPPLY, (E) CONDUIT MEANS CONNEKCTING THE AIRSUPPLY TO EACH OF THE FORWARD AND AFT PEAK TANKS, (F) SEA VALVE MEANSESTABLISHING COMMUNICATION BETWEEN THE WATER AND THE PORTSIDE ANDSTARBOARD TANKS NEAREST SAID TRANSVERSE LINE, (G) OVERFLOW PIPE MEANSEXTENDING BETWEEN ADJACENT ONES OF SAID PORTSIDE AND STARBOARD TANKS ANDSAID FORWARD AND AFT TANKS, RESPECTIVELY, WHEREBY AIR PRESSURE SUPPLIEDTHROUGH SAID CONDUIT MEANS TO SAID FORWARD AND AFT PEAK TANKS WILLSIMULTANEOUSLY FORCE WATER BALLAST IN SAID TANKS TO FLOW FROM THEFORWARD AND AFT PEAK TANKS TOWARD THE MIDSHIP TANKS WHENCE IT ESCAPESTHROUGH THE SEA VALVE MEANS, WHILE WATER ADMITTED THROUGH SAID SEA VALVEMEANS WILL SIMULTANEOUSLY FORCE AIR IN SAID TANKS TO FLOW FROM THEMIDSHIP TANKS TOWARD THE FORWARD AND AFT TANKS, RESPECTIVELY, (H)BALLAST WATER PARTIALLY FILLING SAID BUOYANCY TANKS, THE REMAINDERTHEREOF BEING FILLED WITH AIR, (I) PIPES INTERCONNECTING THE BALLASTWATER IN THE PORTSIDE BUOYANCY TANKS AND IN THE STARBOARD BUOYANCYTANKS, RESPECTIVELY, (J) PIPES INTERCONNECTING THE AIR IN THE PORTSIDEBUOYANCY TANKS AND IN THE STARBOARD BUOYANCY TANKS, RESPECTIVELY, AND(K) PUMPING MEANS DELIVERING BALLAST WATER THROUGH THE INTERCONNECTINGPIPES BETWEEN THE PORTSIDE BUOYANCY TANKS AND THE STARBOARD BUOYANCYTANKS ACCORDING TO THE TRIM REQUIREMENTS.